Today's optical communication networks and systems are continually being required to provide higher and higher communication capacities to meet the demands of increasingly data and information intensive applications and an increased number of users of such applications. To provide higher communication capacities, many optical communication networks and systems are being operated at higher transmission rates and/or with very dense wavelength division multiplexing (DWDM) requiring very dense wavelength spacing and very high speed modulation of DWDM channels. The use of such spacing and modulation is often difficult and tends to add great complexity to optical communication networks and systems. As a consequence, the operation of optical communication networks and systems may become quite costly.
In addition, many of the applications require services which utilize multiple data communication protocols such as IP, ATM, and SONET. One approach to providing such services has been to first multiplex various multi-protocol signals together using TDM or packet techniques, and to then communicate the resulting multiplexed signal on a single wavelength over a DWDM optical communication network. Unfortunately, this approach often requires costly demultiplexing equipment at intermediate sites when a single protocol signal must be dropped, or removed, from the multiplexed signal. Another approach to providing such services, and communicating such multi-protocol signals, has been to utilize separate wavelength channels in a DWDM optical communication network for each of the respective protocols. However, the use of separate wavelength channels may be inefficient and wasteful of the finite number of available optical wavelength channels if one or more of the channels operates at a low data rate.
Therefore, there exists in the industry, a need for a system, including apparatuses and methods, which increases optical communication network or system capacity without necessitating the use of very high speed modulation or very dense wavelength spacing, which enables the dropping of signals without costly demultiplexing equipment, and which addresses these and other related, and unrelated, difficulties and shortcomings.